Fixed Inductors

Part Number	Description / PDF	Quantity
744029006 Würth Elektronik Midcom	FIXED IND 6.8UH 820MA 300 MOHM	1218
744787151 Würth Elektronik Midcom	FIXED IND 150UH 710MA 719 MOHM	1000
744775239 Würth Elektronik Midcom	FIXED IND 390UH 380MA 1.77 OHM	0
74404024068 Würth Elektronik Midcom	FIXED IND 6.8UH 850MA 300 MOHM	2183
74478233 Würth Elektronik Midcom	FIXED IND 33NH 200MA 2.3 OHM SMD	0
744917051 Würth Elektronik Midcom	FIXED IND 5.1NH 1.7A 36 MOHM SMD	100
784383230068 Würth Elektronik Midcom	FIXED IND 680NH 3.1A 60 MOHM SMD	0
74437368047 Würth Elektronik Midcom	FIXED IND 4.7UH 7A 15.5 MOHM SMD	1821
744912156 Würth Elektronik Midcom	FIXED IND 56NH 3A 6.2 MOHM SMD	764
74437358022 Würth Elektronik Midcom	FIXED IND 2.2UH 10A 9.41 MOHM	23
831532200 Würth Elektronik Midcom	FIXED IND 2.2UH 8A 16.4 MOHM SMD	96
7447820039 Würth Elektronik Midcom	FIXED IND 3.9NH 300MA 270 MOHM	0
74405024100 Würth Elektronik Midcom	FIXED IND 10UH 800MA 522 MOHM	329
744777233 Würth Elektronik Midcom	FIXED IND 330UH 390MA 1.86 OHM	3453
744373965068 Würth Elektronik Midcom	FIXED IND 6.8UH 9.5A 11.6 MOHM	699
74406800024 Würth Elektronik Midcom	FIXED IND 240NH 4.1A 19 MOHM SMD	0
7447706471 Würth Elektronik Midcom	FIXED IND 470UH 860MA 610 MOHM	539
784776215 Würth Elektronik Midcom	FIXED IND 150UH 810MA 470 MOHM	0
74437529203330 Würth Elektronik Midcom	FIXED IND 33UH 20.2A 6.9 MOHM	306
74479773147 Würth Elektronik Midcom	FIXED IND 470NH 1.4A 100 MOHM	4562

Fixed Inductors

1. Overview

Fixed inductors are passive electronic components designed to store energy in magnetic fields when electrical current flows through them. Unlike variable inductors, their inductance values remain constant during operation. These components play critical roles in filtering, signal processing, energy storage, and electromagnetic interference (EMI) suppression across modern electronics, including power supplies, communication systems, and automotive electronics.

2. Main Types and Functional Classification

Type	Functional Characteristics	Application Examples
Wirewound Inductors	High precision, high current handling, low resistance	Power supplies, DC-DC converters
Chip Inductors	Compact SMD package, stable performance at high frequencies	Mobile devices, RF circuits
Ferrite Bead Inductors	Effective high-frequency noise suppression	EMI filtering in digital circuits
Thin-Film Inductors	Ultra-compact, high Q-factor, tight tolerance	5G communication modules, IoT devices

3. Structure and Composition

Typical fixed inductors consist of:

Magnetic Core: Made from ferrite, powdered iron, or composite materials to concentrate magnetic flux
Coil Structure: Copper wire wound around the core (enamelled or silver-plated)
Encapsulation: Molded resin or ceramic coating for mechanical protection and insulation
Terminations: Solder-coated ends for PCB mounting (for SMD types) or leaded connections

4. Key Technical Specifications

Parameter	Description	Importance
Inductance (L)	Measured in henrys (H), determines energy storage capacity	Defines filtering/energy storage performance
Rated Current (I_rated)	Maximum DC current before saturation	Prevents core saturation and failure
DC Resistance (DCR)	Resistance of coil windings	Affects efficiency and thermal performance
Self-Resonant Frequency (SRF)	Frequency where inductor behaves as capacitor	Limits effective operating frequency range
Q Factor	Quality factor indicating efficiency	Higher Q = lower energy losses

5. Application Fields

Consumer Electronics: Smartphones, laptops, LED drivers
Industrial Equipment: Motor drives, power inverters
Automotive Systems: ECU modules, EV battery management
Telecom Infrastructure: Base station filters, optical transceivers

6. Leading Manufacturers and Products

Manufacturer	Representative Product	Key Features
Murata	LQH3NPN100M	10 H, 1.2A, 1.8 1.4mm chip inductor
TDK	MLZ2012A100T	100MHz SRF, 1.0 1.25mm for RF circuits
Vishay	IHLP2525CZER1R0M	1 H, 12A, composite construction
Coilcraft	0402DC-103J	10 H, 5% tolerance, ultra-low profile

7. Selection Guidelines

Key considerations during selection:

Calculate required inductance based on switching frequency and ripple current
Verify rated current exceeds maximum operating current by 20-30%
Select SRF higher than circuit operating frequency
Consider package size vs. thermal dissipation requirements
For EMI suppression: Choose ferrite beads with impedance curves matching target frequencies

8. Industry Trends

Current development trends include:

Miniaturization: Sub-0.5mm size inductors for wearable devices
High-Frequency Operation: Components supporting >10GHz 5G applications
Integrated Solutions: Combined inductor-filter modules
Material Innovation: Nanocrystalline cores for higher saturation flux
Automotive Focus: AEC-Q qualified parts for EV/HEV systems